This invention relates to methods and apparatus for providing lifting bails or stirrups in recesses in concrete blocks, and more particularly, to a removable recess-forming insert used for forming recessed pin anchors for the tilting or lifting of concrete wall slabs, cast concrete manholes and the like.
Pre-cast concrete blocks, manholes, and wall slabs need to be moved from place to place at various times. The accustomed method of moving the concrete articles is the utilization of lifting hooks, engaging recessed hoisting bails or stirrups which are embedded in the wet concrete mixture prior to hardening, and, when the concrete hardens, a hoisting cable or hook is engaged with the bail or stirrup and, thus, the article is moved. An important consideration is to ensure that the stirrup is entirely recessed into the cement article so that, when the lifting hook or cable is removed, there are no unwanted projections. Moreover, the stirrup or bail must be firmly anchored in the cement object in order to withstand the rather considerable stresses imposed upon it.
Various methods and devices have been employed to install a bail or stirrup by which the concrete object could be moved. These include the use of both removable and permanent inserts by which a recess is formed to allow access to the lifting stirrup. Both Morley, U.S. Pat. No. 1,045,587 and Forni, U.S. Pat. No. 2,334,206 teach the use of a removable insert which not only molds a recess to access the lifting stirrup but also holds the stirrup in place as the concrete object hardens. Morley utilizes a destructible soft cement mold while Forni uses a wood insert, both of which are knocked out of the concrete object after it hardens. In Saffert, U.S. Pat. No. 2,366,656, a pair of lugs tacked to a base surface form the recess mold, and a cooperating specially manufactured anchor is utilized as the lifting hook for the anchor holding apparatus. In Turner, U.S. Pat. No. 4,087,947, a flexible rubber supporting and pattern ring is glued or cemented to the concrete form wall while supporting an anchor assembly including an anchor bolt, a hangar clip, and a reinforcing rod. The form wall and support/pattern ring are pulled away from the hardened concrete and anchor assembly to allow access to the newly formed hoisting anchor assembly.
Various practical economic problems arise with the use of removable recess forming inserts. Naturally, reusability of the insert is desired as well as facility of its use (i.e., minimum amount of preparation, minimum number of components, etc.). Additionally, it is desirable that the recess forming insert may be used with a standard reinforcing bar or the like, and not require additional hardware. Standard reinforcing bars are used for various other purposes including the reinforcement of concrete slabs and the like, and, therefore, are common at construction sites or other places where concrete slabs may be formed. Moreover, simplicity of its assembly, installation, and removal is highly advantageous.
The present invention incorporates all these desired advantages in a simple and economical package. The insert is formed of elastomeric material whose inherent resilient properties allow for quick and effortless removal from hardened concrete in preparation for the insert's next use, while its simple split block form employing a length of standard reinforcing bar provides an easily attainable and effective hoisting stirrup. Finally, the insert's novel shape allows for easy assembly, installation and removal for re-use.
The coupling of these useful features for the installation of lengths of standard reinforcing bar utilized as hoisting stirrups, and the formation of recesses to access these stirrups is not believed to be disclosed or suggested by any of the prior art patents. The inventor has thus discovered that the novel implementation of a split rubber block performs this operation more simply and effectively than the prior devices and methods.
Accordingly, a principal object of the present invention is to provide a simple but effective means for installing a length of standard reinforcing bar to be utilized as a hoisting stirrup in concrete objects, for the purpose of moving those objects, and for providing access to the hoisting stirrup.
A further object of the invention is to provide an easily installable anchoring device for concrete slabs and the like.
Another object of the invention is to provide a device for installing an anchor, for concrete objects and providing access to the anchor, which anchor can be easily removed and is reusable.
Another object of the invention is to provide a removable recess forming, anchor installing insert which is simple and economical to fabricate.
Another object of the invention is to provide a device for installing a standard reinforcing bar length in a concrete object for use as an anchor and providing an access thereto while requiring no additional equipment or specialized stirrup components.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which: